692 TEXTBOOK OF BOTANY 



19. The embryo is a voiing stage in the development of any indi- 

 vidual. Embryos ma\' develop from fertilized eggs or from vegetative 

 cells. The endosperm is a tissue that develops from a triple-fusion 

 nucleus. Seed coats develop from the coats of the ovule. 



20. The so-called "endosperm" of the gymnosperms is gametophytic 

 tissue and is not analogous to the endosperm of angiosperms. Its cells 

 have the monoploid number of chromosomes. 



21. In the angiosperms, each cell of the embryo has the diploid num- 

 ber of chromosomes, and each cell of the endosperm has the triploid 

 number of chromosomes. 



22. The endosperm of flowering plants is neither gametophyte nor 

 sporophyte, but is an accessorv phase termed the xeniophvte. 



REFERENCES 



Chamberlain, C. J. The Livififi Ci/cads. Univ. of Chicago Press. 1919. 

 Chamberlain, C. J. Gymnosperms, Structure and Evolution. Univ. of Chicago 



Press. 1935. 

 Eames, A. J. Morphologi/ of Vascular Plants. McGraw-Hill Book Company, 



Inc. 1936. 



